Project Summary/Abstract This study will determine whether exercise training influences cognition in overweight children when compared to an attention control condition. This area of research is particularly important due to the increasing rate of overweight and its sequelae among children, which impact minority and disadvantaged populations disproportionately. The aims of this proposal are: 1. To test the hypothesis that exercise training per se can improve executive function. Sedentary, overweight children will be randomly assigned to the after-school exercise program (40 min/d aerobic exercise over 8 mo) vs. an attention control (placebo) condition to isolate the effects of exercise. Executive function measurement approaches will include a psychometric evaluation, a neuropsychological test, and behavior ratings. 2. To determine whether observable changes in brain function result from the exercise training. The experimental hypothesis is that exercise training in sedentary, overweight children will result in changes in the neural circuitry supporting executive functioning during executive function tasks as compared to children assigned to the attention control condition. Additional analyses will include tests of exercise effects on achievement, and possible mediation by executive function; relationships among outcome measures; and planned subgroup analyses to test interactions of age, race and gender with group assignment to assess generalizability of results. Intervention effects will also be evaluated at one-year follow-up. This line of research may have important implications for cognitive development trajectories in children that may affect their long-term achievement. This research program aims to provide evidence to strengthen the basis for policy decisions relating to children's health and education during a childhood obesity epidemic. Project Narrative: Relevance to public health. This research focuses on overweight, sedentary children whose health, cognition, and academic performance are therefore at risk, and who may be particularly responsive to exercise interventions. This study will determine whether regular exercise per se (i.e. compared to attention control, or placebo, condition) benefits children's cognition and achievement, and will provide insight into neural mechanisms. Provision of comprehensive evidence for the benefits of exercise on children's cognition and achievement may reduce barriers to vigorous physical activity programs during a childhood obesity epidemic by persuading policymakers, schools and communities that time spent in physical activity enhances, rather than detracts from, learning.